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去重复sql

发布时间: 2022-04-03 17:32:37

1. sql去除重复的项

  • 假设存在一个主键ID,Name为重复列,下面这句可以查出所有的没有重复的数据:

  • select * from 表 as a where ID=(select min(ID) from 表 where Name=a.Name) 。

  • 根据上面这句就可以删除所有重复项的数据:

  • delete from 表 where ID not in(select ID from 表 as a where ID=(select min(ID) from 表 where Name=a.Name))。

2. SQL查询,如何去除重复的记录

首先,先说明一个问题。这样的结果出现,说明系统设计是有问题的。

其次
删除重复数据,你要提供你是什么数据库
不同数据库会有不同的解决方案。

关键字Distinct 去除重复,如下列SQL,去除Test相同的记录;
1. select distinct Test from Table
2. 如果是要删除表中存在的重复记录,那就逻辑处理,如下:
3. select Test from Table group by Test having count(test)>1
4. 先查询存在重复的数据,后面根据条件删除

还有一个更简单的方法可以尝试一下:
select aid, count(distinct uid) from 表名 group by aid
这是sqlserver 的写法。

  • 如图一在数据表中有两个膀胱冲洗重复的记录。

3. SQL 怎么去除完全重复的数据

用SQL语句,删除掉重复项只保留一条

在几千条记录里,存在着些相同的记录,如何能用SQL语句,删除掉重复的呢
1、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断
select * from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)

2、删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有rowid最小的记录
delete from people
where peopleName in (select peopleName from people group by peopleName having count(peopleName) > 1)
and peopleId not in (select min(peopleId) from people group by peopleName having count(peopleName)>1)

3、查找表中多余的重复记录(多个字段)
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)

4、删除表中多余的重复记录(多个字段),只留有rowid最小的记录
delete from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)

5、查找表中多余的重复记录(多个字段),不包含rowid最小的记录
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)
6.消除一个字段的左边的第一位:
update tableName set [Title]=Right([Title],(len([Title])-1)) where Title like '村%'
7.消除一个字段的右边的第一位:
update tableName set [Title]=left([Title],(len([Title])-1)) where Title like '%村'
8.假删除表中多余的重复记录(多个字段),不包含rowid最小的记录
update vitae set ispass=-1
where peopleId in (select peopleId from vitae group by peopleId

4. sql去除重复数据

测试这样是可以的
select * from table where a in ( select a from table group by a having count(*)<2)

5. 求助SQL去除重复项

select distinct 字段,字段 from 表名
distinct 只能去掉 所有字段都完全相同的数据,即使有一个不相同也不会去重

6. SQL语句 去除重复

select userid,min(username) username,groupid
from table_name
where userid=1
group by userid,groupid
order by 1,3

7. 求SQL消除重复数据语句

select * from #t1
union
select * from #t2
这条语句一起执行是把两个表中唯一的查询出来,如果用union all会把两个表中的结果并集起来

8. sql语句,去重复,求和值

SELECT SUM(b) FROM (SELECT DISTINCT * FROM A)
对于表中两行记录完全一样的情况,可以用下面语句获取到去掉重复数据后的记录:
select distinct * from 表名
将查询的记录放到临时表中

9. 【sql去除重复数据】

select
DISTINCT finger,width,height,size,type
form image
order by finger,width,height,size,type

10. SQL查询去除重复记录

select distinct(*)
from 表名
where 职业="无业"

上边distinct 就是去除重复的关键字